A20/NF-kB Reporter (Luc) cells are derived from the mouse B lymphocyte cell line A20 by stably integration of a NF-kB firefly luciferase reporter construct. A20 cells were derived from a spontaneously arising reticulum cell sarcoma from an aging BALB/c mouse. A20 cells are highly responsive to immunomodulatory antibodies. A20 /NF-kB Reporter (Luc) cells stably express firefly luciferase under the control of the NF-kB response elements, can be used for monitoring the activity of NF-kB signaling pathway.